Propane is about as simple as it gets! If you search around a little the parts can be found pretty cheap as well. As far as running down the road and getting "fuel"(propane in this case) it is pretty simple. If you have never noticed there are several places that sell propane.

On a side note: Propane burns much cleaner and if properly tuned right you will get more power out of the engine.

I have worked on industrial engine propane systems for a number of years so I'm familiar with the in's and out's. I still maintain that a properly set up EFI system is superior to propane in an off road application, in my opinion. To each their own. In industry, the only reason propane power is used verses gas or diesel is because the piece of equipment being used will be operated indoors.